1. Field of the Invention
The present invention generally relates to printing devices operating in conjunction with host computers and more particularly to printers connected to a host computer that provide output in response to commands from the host computer. The invention further relates to point-of-sale type printers capable of printing on cut-sheet type paper.
2. Related Technology
A variety of small specialized printers have been developed and widely used with host computers and other apparatus for printing data associated with point-of-sale (POS) transactions. A common example of such a printer application is for a department store where such printers are used to generate a "tape" style purchase receipt on "recording paper" for a customer which lists the items purchased as well as taxes and other fees levied against the transaction and a total balance due. These printers are used as part of the so called cash or check-out "register" commonly seen throughout retail business. In addition to the recording paper, these printers are also generally required to generate a "journal" or "journal tape" on a roll of paper for permanently recording and verifying the transactions for the particular sales register.
The printing devices used for these kinds of transactions generally transported a recording paper material, typically from a roll of paper, along a preset paper path through a printing mechanism where a print head forms the output image. More recently, due to the nature of record keeping and the sales transactions themselves, single or "cut-sheet" paper has found use in sales transactions. Additional information, business logos, instructions, or terms and conditions of the sale are now included as part of the transaction receipt, or specialized transaction forms, such as for "credit" transactions, are used. Therefore, many POS printers are configured with an insertion or access slot to provide access for insertion of individual cut-sheet paper or forms into the paper path for the printing mechanism.
In any case, POS printers are currently configured to begin printing immediately, when a switch is activated by an operator, or within a set elapsed time after it is determined that paper has been inserted into the mechanism, particularly cut-sheet paper. Since the time it takes to position recording paper in POS printers, and the like, varies according to operator skill or experience, this currently gives rise to two inefficient conditions. First, an operator may be required to wait until the end of an allotted elapsed time interval even after the recording paper is positioned within the printer. Second, once the recording paper is detected, regardless of whether or not correctly positioned, it is transported into or through the printer before being correctly positioned, often causing problems.
On the other hand, if a maximum waiting time for insertion of recording paper is not set, the host computer will wait indefinitely until it receives information from the printing device regarding insertion of the recording paper, also resulting in lost time. At the same time, if an operator mistakenly sets the printer in a cut-sheet paper printing mode, it is sometimes necessary to turn off the power to the printer to escape this mode, which also resets other settings.
What is needed is a method and apparatus for setting and changing waiting times for paper insertion, positioning, and transport which can flexibly account for the skill of the operator. Something is needed to optimize the allocation of time for POS paper insertion activities while facilitating host control through application of new transport control commands.